A wellbore is formed using a drill bit that is urged downwardly at a lower end of a drill string. In the process of forming a wellbore, it is sometimes desirable to utilize various tripping devices to control a downhole tool. Tripping devices are typically dropped or released into the wellbore to operate a downhole tool. The tripping device usually lands in a seat of the downhole tool, thereby causing the downhole tool to operate in a predetermined manner. Examples of tripping devices, among others, include balls, plugs, and darts.
For example, a ball is dropped onto a seat located in the wellbore to close off the wellbore. Sealing off the wellbore allows pressure to be built up to actuate a downhole tool such as a packer, a liner hanger, or a running tool. The ball may be dropped to shear a pin to operate a downhole tool. There are drawbacks to using tripping devices such as a ball. Such drawbacks are the number of times they can be used, reliability, size of the tripping device, effecting down time, down time for a ball to reach its destination, and costs.
Other ways of operating a downhole remotely is to use a wire line, an electric cable from the surface to the downhole tool. This causes the problem of arranging and maintaining the wire line from the surface all the way down. A further way is to operate a downhole tool remotely by using a remotely controlled activating device. This has the significant drawback of needing an electric power source in the form of a battery. Batteries are not allowed in certain environments of a wellbore because of fire hazard. Downhole tools with batteries require strict limitations and regulations for transportations. Often a tool with a battery is simply not allowed or desired in the oil and gas industry.